东海外陆架晚第四纪沉积物的稀土元素组成及物源示踪

Distribution of Rare Earth Elements in Late Quaternary Sediments on the Outer Shelf of the East China Sea and Their Source Tracing

为研究东海外陆架稀土元素地球化学信息对于地层划分与物源分析的指示意义，利用电感耦合等离子体质谱仪（ICP-MS）对东海外陆架西湖凹陷区SFK-1孔沉积物进行了15个稀土元素（REE）含量测定。东海外陆架 SFK-1孔稀土元素含量及比值变化表现出一定的分层性，垂向上自上而下可分为8层，表明稀土元素特征对于地层划分具有良好的指示意义。稀土元素分配模式表明SFK-1孔沉积物物源主要为长江和黄河， Eu异常与稀土元素总量关系判别图解和物源判别指数（PI）揭示SFK-1孔上部28.00 m以上沉积物以长江源为主，中部28.00-47.20 m沉积物以黄河源为主，下部47.20-82.90 m沉积物以长江源为主。研究表明长江从晚更新世早期到现代对东海陆架起着主要作用，而黄河物质在晚更新世晚期已开始对东海陆架沉积作用有一定影响。

The sediment samples collected from Core SFK-1 in the depression area of Xihu on the outer shelf of the East China Sea were measured for rare earth elements （REE） by using ICP-MS with the purpose of studying the indicator significance of REE geochemical information for the stratigraphic division and provenance analysis of the outer shelf sediments in the East China Sea. According to the variation of REE content and ratio, the sediments from Core SFK-1 can be divided into eight geochemical layers, suggesting that geochemical characteristics of REE have good indicator significance for stratigraphic division. The results show that the sediments in Core SFK-1 were mainly derived from the Yangtze River and the Yellow River. The sediments above the depth of 28.00 m in upper Core SFK-I mainly belong to the Yangtze River source; the sediments between 28.00-47.20 m in middle Core SFK-1 was mainly derived from the Yellow River, and the sediments between 47.20 and 82.90 m at the bottom of Core SFK-1 was mainly derived from the Yangtze River. It is concluded that the Yangtze River has been playing a main role in the continental shelf of East China Sea since early Late Pleistocene and the Yellow River started to influence the continental shelf sedimentation of the East China Sea at the late stage of Late Pleistocene.